At work, we have a lot of IBM Netvista's. We've found the last 3 captial equipment cycles feature a "nice" feature of buldging capacitors. I would open your case and see if the capacitors around the CPU are buldging / leaking goo stuff. If so. contact IBM and see if they will replace it, you may get lucky. In rare case we've had the leaking capacitor issue in the power supply too but was very rare.

Hellson I feel your pain!
I have a friend of mine who purchased a dozen of the 6648 machines in an off-lease purchase from one of the local "whitebox" builders. I bought one in a pinch because of time constraints for me building my own (as I normally do). We have had the machines since Jan '04 with legit W2K licenses and set them up to run. We have always been fond of off-lease machines for the cost savings to new and have had great luck with the old Compaq Deskpros. We decided to try the IBMs since the Compaqs went dry. For the last two months we have tried to figure out why thre machines my friend has have the mentioned symptoms you have. Then my machine started doing it a couple of weeks ago. That makes four. Imagine that the original warranty on my machine according to IBM ended in May '04 and now it is dying. Old big blue has let me down and apparently others too. I've seen bulging caps on other MBs (Abit, Asus, MSI, & Gigabyte) and power supplies too dating from the time when this machine was produced. I want to see what IBM says about this when I email them. I would like to thank Communist China and the American public for embracing the Communists so that we may have cheap pieces of s**t like this that give good old American companies a bad rep. Whew!